People who add a lot of smiley faces in their formal communications at work for no reason. I have very little trust for them!

Some just display their personality (which belongs in emotions in so many ways) in different ways than you? But yes if you trust those who are all serious who don't use emoji's than that's you. I use emoji's with people mostly how they use them, if they love using them, I use them with them because I know it's part of how they communicate. It's rather simple without needing to be overthought